CORALS AND BRYOZOA. 7 



marked by very strong longitudinal striae, increasing in number with the 

 size of the cell tube and giving to the margins of the walls a crenulated 

 appearance. Mural pores large, circular, invariably occurring on the longi- 

 tudinal ridges. 



This is the most robust species of the genus yet noticed, and the cells are 

 large in proportion ; it is not a common form and is generally found in detached 

 pieces on the weathered surfaces of blocks of limestone. 



Formation and locality. In limestones of the Lower Helderberg group, Clarks- 

 ville, N. Y. 



MICHELINIA, De KoNiNCK. 1842. 



MiCHELINIA LENTICDLARIS. 



PLATE III, FIGS. 1,2,3,5. 



Michelinia Unticularis, Hall. Twenty-sixth Kept. N. Y. State Mus. Nat. Hist., p. 113. 1874. 



Thirty-second Kept. N. Y. State Mus Nat. Hist., p. 14.'). 1879. 

 " Report of State Geologist for 1883. Expl. pi. 3, figs 1, 2, 3, 5. 1883. 



CoRALLUM forming small lenticular bodies, the lower surface usually the less 

 convex and covered with a strongly wrinkled epitheca. Cells large and few, 

 usually from seven to twelve ; broiidly campanulate. Partition walls about 

 1 mm. thick ; strongly marked longitudinally by nodose striations ; den- 

 ticulate on the margins. The number of striations and denticulations varies 

 with the size of the cell. 



In a characteristic specimen 20 mm. in diameter, there are eight cells, the 

 central one having a diameter of 11 mm., and the peripheral cells measuring 

 from 6 to 8 mm. across. The entire height of this specimen is 9 mm. 



This is a very small species, seldom attaining a diameter, of more than 25 

 mm., and is distinguished by its large cells and their strongly granulose-striate 

 character. A small individual 10 mm. in diameter shows one large central 

 cell and six smaller ones around the margin, also an incipient seventh cell. 

 Occasionally there are two central cells in large individuals, and the number of 

 peripheral cells in such specimens is from ten to twelve. 



Formation and localities. In the shaly limestone of the Lower Helderberg 

 group, near Clarksville and Schoharie, N. Y. 



